They have tasted foods abroad, invested in cooking equipment and cooking lessons. They have read the great food writers, watched TV's Julia Child, and practiced making foreign dishes from French and Greek to Chinese.

People are making more things from scratch but they feel free to serve store-bought foods if they're good.

One thing is quite clear: The groaning board, the Thanksgiving Day table laden with food that takes weeks of cooking and baking ahead, is a relic of the past.

The trend today is for a lighter holiday meal with emphasis on fresh fruits and vegetables.

These fresh foods, often home-grown and even wild, give a wider variety to choose from. Young American chefs, whether trained here or abroad, are the single most vital force revolutionizing how and what we eat.

They are using ingredients such as wild mushrooms, Jerusalem artichokes, sugar snap peas, spaghetti squash, fennel, papaya, elderberries, rose hips, nuts , venison, pheasant, and quail - to name only a few.

Some of these foods are as traditional as turkey, cranberries, and pumpkin if you consider foods served at the very first Thanksgiving Day celebrations years ago. Others have always been available, but just not as popular.

Some purists claim that the first Thanksgiving dinner was not held in Virginia or Plymouth but on the coast of Maine in 1607 at the Popham Colony. There the menu was not turkey or game but a feast of lobster, clams, and oysters.

But all of the change this year is not a change of basic foods; some cooks and chefs are using the traditional foods but cooking and serving them in a different way and in unusual combinations.

Others are simply serving smaller portions of very carefully cooked dishes, arranged on the plates artistically in a rather Japanese style.

All around the United States there are indications of a new, flexible approach to the way ingredients are put -together and the way a meal is planned.

Courses are not always served in the order of soup, meat and vegetables, then dessert. Some cooks serve first the dish they like the best.

One young chef, Larry Forgione, has planned a holiday menu around a native American meat, venison. The deer eats cranberries, carrots, and other wild foods , therefore they all go together naturally and they all taste well together, he explains.

He serves Herbed Quail Eggs or Roulade of Michigan Buffalo with White Oak Acorns as the hors d'oeuvre. Then the Mignon of Venison is served with two sauces, cranberry and mushroom; and a salad of wild lettuces, flowers, and herbs - all American foods, fresh and in season.

Chef Forgione's menu at the River Cafe under the Brooklyn Bridge is a showcase for the finest and most unique American foods he can find.

His Thanksgiving menu will also include wild turkey from New Hampshire, salmon trout from California, pheasant, partridge, and wild duck.

Desserts include Calastoga Cheese Cake with fresh strawberries, traditional pumpkin pie, a Chocolate Pate with four kinds of chocolate, and Poached Comice Pears Princess Grace, which Chef Forgione created when the princess came to his Brooklyn restaurant.

Filled with ice cream, the pears, in a cookie shell, are topped with a puree of fresh raspberries.

While America's contribution to world cooking in the past has been largely in appliances, gadgets, and convenience foods, its recipes have not been widely copied by people elsewhere. Ocean Spray, a large cranberry cooperative, is working to change that image by commissioning both American and foreign chefs to create new dishes using American-grown ingredients, including cranberries, of course.

The results have been pretty spectacular. Many dishes did not include the berries, but there were recipes such as Cold Cranberry Orange Soup with Pear Balls by John Terczak of Gordon &amp; Leaner restaurants in Chicago, Cranberry Sorbet with Seasonal Fruits Gratin by Chef Franz Kuhne of Hilton International in Basel, Switzerland, and Cranberry Chocolate Cake created by Alice Medrich of Cocolat in San Francisco.

Christian DeVos, executive chef at the Jared Coffin House in Nantucket, Mass. , knew little about American food when he came to this country a few years ago, but he is convinced that it is the only food that should be served at this historic inn.

He takes pride in creating menus that are new and imaginative and which make the most use of local products in new and different ways.

On Thanksgiving Chef DeVos will serve a traditional dinner for the many families that make reservations months ahead. Also on the menu are two dinners based on island foods, Nantucket Scallops with Julienne of Vegetables - carrots, leeks, celery, and herbs; and Nantucket Pheasant with Beach Plum Sauce.

Chef DeVos prefers serving smaller portions with the option of second helpings but he admits that on this holiday people like to see a generously filled plate.

One new hotel already making a name for its American cuisine is New York City's Vista International. This will be the first Thanksgiving for its American Harvest restaurant where guests can choose Maryland Crab Bisque or Butternut Squash-Apple Soup to start the holiday meal.

There will also be fresh oysters from the eastern shore, fruit cup, acorn fritters, and pheasant pate.

After two years of research for American recipes from all regions of the United States, consultant Margaret Spader says this hotel's Thanksgiving Day menu reads like a gastronomic tour of the country.

There are Pensylvania Dutch sweets and sours on the relish tray and a Cranberry Orange Relish Salad with Celery Seed Dressing with the main course.

Roast turkey will be stuffed with Georgia Pecan Stuffing since some researchers believe nut stuffings originated among the Indians of the Southeast, particularly the Cherokee, Catawba, and Chickasaw tribes.

Alternates to turkey, here, are Country Ham, Twin Tenderloin of Beef, Rack of Lamb Stuffed with Spinach, and Broiled Halibut on Julienne of Autumn Vegetables.

Virginia Spoonbread made with white, water-ground cornmeal will be served in individual casseroles.

The pastry kitchen's Double Chocolate Roll will also have a place on the dessert trolley because it is so popular, even though it's not traditional.

James Beard, the cookbook writer often called the dean of American cookery, told me about the Union Hotel Restaurant - one of the nicest, honest-to-goodness American restaurants in the United States.

A traditional Thanksgiving dinner will be served here in this restored small hotel in Benecia, a sleepy little town 45 minutes from San Francisco. It was the capital of California for one year - in 1853. Young Chef Judy Rogers serves fresh, wholesome food cooked simply but very carefully and well.

Although her training was in French cooking, Chef Rogers believes American cuisine can become as reputable as French or Italian food if it is prepared with the same careful attention. Everything is cooked to perfection and nothing is covered or disguised with mysterious or heavy sauces.

She believes everything can be cooked from scratch, in restaurants as well as at home. ''Hamburgers wouldn't be junk food if you grind your own hamburger and bake your own buns,'' she said.

Although there will be a traditional roast turkey dinner on the Union Hotel menu, Chef Rogers's Roasted Duck or Quail with Wild Rice Waffles, which I found to be superb, would be an equally good Thanksgiving Day entree.

Pennsylvania Dutch Eggs and Pickled Beets were the starters and I also had a Parsley Salad made with parsley flowerets tossed with Parmesan cheese, oil, and vinegar, along with tissue-thin slices of Smithfield ham.

Desserts include an old-fashioned Indian pudding and equally nice Burnt Cream , a rich custard topped with hardened sugar.

Thanksgiving Day may not be a time to observe the changes in our eating habits. But there is no question the trend today is toward more simple and honest dishes made of our own wonderful abundance of fresh home-grown fruits, vegetables, meats, and fish - the makings of a distinctive American cuisine.

There is no question that there is an element of faddism and affectation in some of the unorthodox food combinations, and there always are a certain number of people who follow fads slavishly.

But there are plenty of more sensible people who are also creative, so don't be too quick to scorn what may seem an odd-sounding combination. Often these new dishes that sound far out are not only edible, but surprisingly good.